.chess {
    width: var(--chess-width);
    height: var(--chess-width);
    border: 2px solid lightgray;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-sizing: border-box;
}

.chess-item {
    width: 30px;
    height: 30px;
    border-radius: 50%;
}

.red {
    background: radial-gradient(#fff, #f20)
}

.black {
    background: radial-gradient(#fff, black);
}